Monocyte activity is linked with abdominal aortic aneurysm diameter

Background

Systemic inflammation and increased matrix metalloproteinase (MMP) cause elastin degradation leading to abdominal aortic aneurysm (AAA) expansion. Several prospective studies report that statin therapy can reduce AAA expansion through anti-inflammation. We hypothesize that monocyte activity plays a pivotal role in this AAA development and this study examines patient peripheral blood monocyte cell adhesion, transendothelial migration, and MMP concentrations between AAA and non-AAA patients.

Materials and methods

Peripheral blood was collected and monocytes isolated from control (n = 15) and AAA (n = 13) patients. Monocyte adhesion, transmigration, and permeability assays were assessed. Luminex assays determined MMP-9 and tissue inhibitor of metalloproteinase-4 (TIMP-4) concentrations from cell culture supernatant and patient serum.

Results

AAA patient monocytes showed increased adhesion to the endothelium relative fluorescence units (RFU, 0.33 ± 0.17) versus controls (RFU, 0.13 ± 0.04; P = 0.005). Monocyte transmigration was also increased in AAA patients (RFU, 0.33 ± 0.11) compared with controls (RFU, 0.25 ± 0.04, P = 0.01). Greater numbers of adhesive (R² = 0.66) and transmigratory (R² = 0.86) monocytes were directly proportional to the AAA diameter. Significantly higher serum levels of MMP-9 (2149.14 ± 947 pg/mL) were found in AAA patients compared with controls (1189.2 ± 293; P = 0.01). TIMP-4 concentrations were significantly lower in AAA patients (826.7 ± 100 pg/mL) compared with controls (1233 ± 222 pg/mL; P = 0.02). Cell culture supernatant concentrations of MMP and TIMP from cocultures were higher than monocyte-only cultures.

Conclusions

Monocytes from AAA patients have greater adhesion and transmigration through the endothelium in vitro, leading to elevated MMP-9 levels and the appropriate decrease in TIMP-4 levels. The ability to modulate monocyte activity may lead to novel medical therapies to decrease AAA expansion.     

Antioxidant Vitamin C attenuates experimental abdominal aortic aneurysm development in an elastase-induced rat model

Background

We investigated the hypothesis that an antioxidant, Vitamin C, could attenuate abdominal aortic aneurysm (AAA) development in a rat model.

Methods

An AAA model induced by intraluminal infusion was created in 36 male Sprague Dawley rats, which were randomly distributed into three groups: Sham (saline infused, placebo treated), Control (elastase infused, placebo treated), and Vitamin C (elastase infused, vitamin C treated). Vitamin C and placebo were intraperitoneally injected, initiating 1 wk before the infusion and continuing throughout the study. The aortic dilatation ratio was measured, and aortic tissues were further examined using biochemical and histologic techniques.

Results

Vitamin C attenuated the development of AAA, decreasing maximal aortic diameter by 25.8% (P < 0.05) and preserving elastin lamellae (P < 0.05). Vitamin C also decreased 8-hydroxyguanine (a marker of oxidative damage to DNA) and 8-isoprostane content (a marker of oxidative stress) in aortic tissues (P < 0.05, respectively). The proteins of matrix metalloproteinase (MMP)-2, MMP-9, and interleukin 6 were markedly downregulated (P < 0.05, respectively), accompanied with notably reduced messenger RNA expression of tumor necrosis factor-α, MMP-2/9, and interleukin 1β (P < 0.05, respectively). However, messenger RNA of tissue inhibitors of metalloproteinase-1 and tissue inhibitors of metalloproteinase-2 were both significantly upregulated in Vitamin C group. Vitamin C treatment had no significant effect on systolic blood pressure (P > 0.05).

Conclusions

Vitamin C attenuated AAA development in an elastase-induced rat model via crucial protective effect, which was mediated by an increased level of antioxidant in cooperation with preserving elastin lamellae, inhibiting matrix-degrading proteinases and suppressing inflammatory responses.     

Percutaneous valved stent implantation in the ascending aorta for the treatment of very high-risk aortic regurgitation: an animal study

Purpose

We investigated the effects of percutaneous valved stent implantation in the ascending aorta as an alternative treatment for aortic regurgitation in a canine model.

Materials and methods

A total of 16 healthy dogs weighing an average of 18.3 ± 2.1 kg were used for the establishment of animal models of chronic aortic regurgitation by percutaneous aortic valve perforation and balloon dilation. At 2 mo after successful model establishment, all experimental animals underwent valved stent implantation in the ascending aorta and then were followed up for 3 mo.

Results

Experimental models of chronic aortic regurgitation were successfully established in 10 dogs. Surviving dogs underwent successful valved stent implantation in the ascending aorta and were subsequently followed up for 3 mo. The level of instantaneous aortic regurgitation at 3-mo follow-up was significantly reduced compared with that before valved stent implantation (2.4 ± 0.9 versus 10.6 ± 2.1 mL/s, P < 0.05). The left ventricular ejection fraction was significantly increased (53.8 ± 4.2% versus 37.8 ± 3.7%, P < 0.05), and the left ventricular end-diastolic volume was also significantly reduced (30.3 ± 2.2 versus 40.1 ± 3.6 mL, P < 0.05). No paravalvular leak, stroke, atrioventricular block, or other complications occurred in dogs undergoing valved stent implantation.

Conclusions

Percutaneous valved stent implantation in the ascending aorta is feasible, effective, and safe as an alternative treatment for very high-risk aortic regurgitation in a canine model.     

Dexmedetomidine protects against ischemia–reperfusion injury in rat skeletal muscle

Background

Dexmedetomidine (DEX) has been shown to decrease ischemia–reperfusion (I/R) injury in kidney and brain tissues. In this study, the effects of DEX were evaluated in skeletal muscle during I/R injury.

Materials and methods

Animals were divided into four groups: sham-operated (sham group), saline + I/R, DEX + I/R, and α-tocopherol + I/R groups. Hind limb ischemia was induced by clamping the common femoral artery and vein. After 4 h of ischemia, the clamp was removed and the animals underwent 2 h of reperfusion. Animals in the drug treatment group received DEX or α-tocopherol by intraperitoneal injection 1 h before reperfusion. We measured plasma concentrations of interleukin 1β and tumor necrosis factor α levels using an enzyme-linked immunosorbent assay. The right gastrocnemius muscle was harvested and immediately stored at −80°C for the assessment of superoxide dismutase (SOD) and catalase (CAT) activities as well as glutathione (GSH), malondialdehyde (MDA), and protein oxidation (PO) levels. DEX (25 μg/kg) and normal saline (10 mL/kg) were administered by intraperitoneal injection 1 h before reperfusion.

Results

Plasma tumor necrosis factor α or interleukin 1β levels increased significantly in the I/R group (P < 0.01 compared with sham group) and decreased significantly in the DEX group (P < 0.01 compared with I/R group). Muscle tissues of the I/R group had significantly decreased SOD, GSH, and CAT activities and increased levels of MDA and PO content compared with the sham group. The activity of antioxidant enzymes in the DEX + I/R group was greatly elevated compared with that in the I/R group (SOD, 1.068 ± 0.120 versus 0.576 ± 0.072 U/mg protein; GSH, 2.436 ± 0.144 versus 1.128 ± 0.132 μmol/g; and CAT, 69.240 ± 6.456 versus 31.884 ± 6.312 U/mg protein; P < 0.01), whereas the levels of MDA and PO content were clearly reduced (23.268 ± 3.708 versus 53.604 ± 5.972 nmol/g protein and 1.908 ± 0.192 versus 5.208 ± 0.612 nmol/mg protein, respectively; P < 0.01). Moreover, DEX exhibited more potent antioxidant activity than vitamin E in the skeletal muscle I/R.

Conclusions

We found that DEX exhibits protective effects against skeletal muscle I/R injury. These results underscore the necessity of human studies with DEX to determine if it is beneficial for preventing skeletal muscle I/R injury.     

Ghrelin decreases motor deficits after traumatic brain injury

Background

Pharmacologic therapy for traumatic brain injury (TBI) has remained relatively unchanged for decades. Ghrelin, an endogenously produced peptide, has been shown to prevent apoptosis and blood-brain barrier dysfunction after TBI. We hypothesize that ghrelin treatment will prevent neuronal degeneration and improve motor coordination after TBI.

Materials and methods

A weight drop model created severe TBI in three groups of BALB/c mice: Sham, TBI, and TBI + ghrelin (20 μg intraperitoneal ghrelin). Brain tissue was examined by hematoxylin and eosin and Fluoro-Jade B (FJB) staining to evaluate histologic signs of injury, cortical volume loss, and neuronal degeneration. Additionally, motor coordination was assessed.

Results

Ghrelin treatment prevented volume loss after TBI (19.4 ± 9.8 mm³versus 71.4 ± 31.4 mm³; P < 0.05). Similarly, although TBI increased FJB–positive neuronal degeneration, ghrelin treatment decreased FJB staining in TBI resulting in immunohistologic patterns similar to sham. Compared with sham, TBI animals had a significant increase in foot faults at d 1, 3, and 7 (2.75 ± 0.42; 2.67 ± 0.94; 3.33 ± 0.69 versus 0.0 ± 0.0; 0.17 ± 0.19; 0.0 ± 0.0; P < 0.001). TBI + ghrelin animals had significantly decreased foot faults compared with TBI at d 1, 3, and 7 (0.42 ± 0.63; 0.5 ± 0.43; 1.33 ± 0.58; P versus TBI <0.001; P versus sham = NS).

Conclusions

Ghrelin treatment prevented post-TBI cortical volume loss and neurodegeneration. Furthermore, ghrelin improved post-TBI motor deficits. The mechanisms of these effects are unclear; however, a combination of the anti-apoptotic and inflammatory modulatory effects of ghrelin may play a role. Further studies delineating the mechanism of these observed effects are warranted.     

Comparison of surgical outcomes between papillary thyroid cancer patients treated with the Harmonic ACE scalpel and LigaSure Precise instrument during conventional thyroidectomy: a single-blind prospective randomized controlled trial

Background

The aim of this study was to evaluate the safety and efficacy of thyroidectomy using the Harmonic ACE scalpel (HS) or the LigaSure Precise (LS) instrument in conventional thyroidectomy.

Materials and methods

A prospective, randomized controlled trial was performed. Between August 2011 and June 2012, 832 patients who required thyroidectomy for papillary thyroid cancer were randomized into groups treated with either the HS or the LS instrument. Operative time and surgical morbidities were analyzed.

Results

A total of 320 patients (HS group, N = 164; LS instrument group, N = 156) were randomized for analysis according to the intention-to-treat principle. There were no statistically significant differences in the operative times (HS group versus LS instrument group: 71.93 ± 18.26 versus 75.15 ± 20.13; P = 0.423), postoperative transient hypoparathyroidism (13.4% versus 14.1%; P = 0.858), and permanent recurrent laryngeal nerve injuries between the two groups.

Conclusions

In this study, both hemostatic devices were safe and effective in terms of postoperative results and complications without any differences.     

Remote ischemic perconditioning protects the liver from ischemia–reperfusion injury

Background

Ischemia–reperfusion (IR)–induced injury is a frequent sequel of major liver resections. IR injury after prolonged surgical interventions could be the source of increased risk of postoperative morbidity and mortality. Hepatoprotective effects of this new feasible method called remote ischemic perconditioning (RIPER) were investigated in our rat model of IR injury.

Materials and methods

Male Wistar rats underwent ischemia for 60 min on two-thirds of their livers, followed by 1, 6, and 24 h of reperfusion (n = 72, 8 per group). During liver ischemia, but before reperfusion, rats in the treated groups received four cycles of brief infrarenal aortic clamping as perconditioning. Liver microcirculation was monitored by laser Doppler flowmeter parallel with mean arterial pressure measurements. Liver tissue injury and redox homeostasis were investigated. Furthermore, serum tumor necrosis factor alpha (TNF-α) levels were measured.

Results

In the RIPER group, compared with the IR group, serum transaminase levels were significantly lower after each reperfusion period (alanine aminotransferase: 1 h, P < 0.001; 6 h, P < 0.05; 24 h, P < 0.01 and aspartate aminotransferase: 1 h, P < 0.001; 6 h, P < 0.05; 24 h, P < 0.05). Reperfusion microcirculatory parameters significantly improved in the perconditioned group compared with those in the IR group (reperfusion area: P = 0.005; maximal plateau: P = 0.0002). Regarding TNF-α levels, significant differences were detected between the two IR injured groups (RIPER versus IR: 1 h, 34.3 ± 12.8 pg/mL versus 205.7 ± 60.9 pg/mL, P < 0.001; 6 h, 60.6 ± 11.7 pg/mL versus 110.4 ± 21.6 pg/mL, P < 0.05). Results of the histologic assessment and redox state measurements also showed favorable changes.

Conclusions

Our team firstly reported the protective effects of RIPER on liver morphology, redox homeostasis, and microcirculation and proposed the changes of TNF-α expression.     

Fenofibrate does not affect burn-induced hepatic endoplasmic reticulum stress

Background

Burn injury causes major metabolic derangements such as hypermetabolism, hyperlipidemia, and insulin resistance and is associated with liver damage, hepatomegaly, and hepatic endoplasmic reticulum (ER) stress. Although the physiological consequences of such derangements have been delineated, the underlying molecular mechanisms remain unknown. Previously, it was shown that fenofibrate improves patient outcome by attenuating postburn stress responses.

Methods

Fenofibrate, a peroxisome proliferator–activated receptor alpha agonist, regulates liver lipid metabolism and has been used to treat hypertriglyceridemia and hypercholesterolemia for many years. The aim of the present study is to determine the effects of fenofibrate on burn-induced hepatic morphologic and metabolic changes. We randomized rats to sham, burn injury, and burn injury plus fenofibrate. Animals were sacrificed and livers were assessed at 24 or 48 h post burn.

Results

Burn injury decreased albumin and increased alanine transaminase (P = 0.1 versus sham), indicating liver injury. Fenofibrate administration did not restore albumin or decrease alanine transaminase. In addition, ER stress was significantly increased after burn injury both with and without fenofibrate (P < 0.05 versus sham). Burn injury increased fatty acid metabolism gene expression (P < 0.05 versus sham), downstream of peroxisome proliferator–activated receptor alpha. Fenofibrate treatment increased fatty acid metabolism further, which reduced postburn hepatic steatosis (burn versus sham P < 0.05, burn + fenofibrate versus sham not significant).

Conclusions

Fenofibrate did not alleviate thermal injury–induced hepatic ER stress and dysfunction, but it reduced hepatic steatosis by modulating hepatic genes related to fat metabolism.     

The effect of fluoxetine on ischemia–reperfusion after aortic surgery in a rat model

Background

Aortic ischemia–reperfusion (IR) is an important factor in the development of postoperative acute lung injury after abdominal aortic surgery. The aim of the present study was to examine the effect of fluoxetine (Flx), a selective serotonin reuptake inhibitor widely used as a preoperative anxiolytic, on lung injury induced by abdominal aortic IR in rats.

Methods

Wistar rats were randomized into three groups (n = 7 per group): (1) control (sham laparotomy); (2) IR without Flx (60-min ischemia and 120-min reperfusion); (3) IR with Flx (Flx + IR) (Flx 20 mg/kg/d, intraperitoneally for 3 d before surgery). Lung tissue samples and bronchoalveolar lavage (BAL) were obtained for biochemical analysis of oxidative status. Ischemia-modified albumin (IMA) level and protein concentrations in BAL and lung wet to dry weight ratios were determined. Histologic evaluation of the lung tissues was also performed.

Results

IR without Flx led to significant increase in lipid hydroperoxide, malondialdehyde, and pro-oxidant–antioxidant balance and decrease in superoxide dismutase, glutathione, and ferric reducing antioxidant power activities (P < 0.05 versus control), whereas Flx was able to restore these parameters (P > 0.05 versus control) and decrease IMA level (P < 0.01 versus control) and protein concentration (P < 0.05 versus control) in BAL and wet to dry lung weight ratio. Histologic evaluation showed that Flx attenuated the morphologic changes associated with lung injury.

Conclusions

The results indicate that Flx confers protection against aortic IR-induced lung oxidative stress and cellular integrity. IMA levels in BAL may be used as a follow-up marker for the efficacy of treatment in lung injury.     

Membrane potential-dependent uptake of F-triphenylphosphonium–a new voltage sensor as an imaging agent for detecting burn-induced apoptosis

Background

Mitochondrial dysfunction has been closely related to many pathologic processes, such as cellular apoptosis. Alterations in organelle membrane potential are associated with mitochondrial dysfunction. A fluorine-18 labeled phosphonium compound: ¹⁸F-triphenylphosphonium (¹⁸F-TPP) was prepared to determine its potential use as a mitochondria-targeting radiopharmaceutical to evaluate cellular apoptosis.

Methods

Studies were conducted in both ex vivo cell lines and in vivo using a burned animal model. Uptake of ¹⁸F-TPP was assessed in PC-3 cells by gamma counting under the following conditions: graded levels of extracellular potassium concentrations, incubation with carbonyl cyanide m-chlorophenylhydrazone and staurosporine. Apoptosis was studied in a burn animal model using terminal deoxynucleotidyl transferase dUTP nick end labeling staining and simultaneous assessment of ¹⁸F-TPP uptake by biodistribution.

Results

We found that stepwise membrane depolarization by potassium (K) resulted in a linear decrease in ¹⁸F-TPP uptake, with a slope of 0.62 ± 0.08 and a correlation coefficient of 0.936 ± 0.11. Gradually increased concentrations of m-chlorophenylhydrazone lead to decreased uptake of ¹⁸F-TPP. Staurosporine significantly decreased the uptake of ¹⁸F-TPP in PC-3 cells from 14.2 ± 3.8% to 5.6 ± 1.3% (P < 0.001). Burn-induced significant apoptosis (sham: 4.4 ± 1.8% versus burn: 24.6 ± 6.7 %; P < 0.005) and a reduced uptake of tracer in the spleens of burn-injured animals as compared with sham burn controls (burn: 1.13 ± 0.24% versus sham: 3.28 ± 0.67%; P < 0.005). Biodistribution studies demonstrated that burn-induced significant reduction in ¹⁸F-TPP uptake in spleen, heart, lung, and liver, which were associated with significantly increased apoptosis.

Conclusions

¹⁸F-TPP is a promising new voltage sensor for detecting mitochondrial dysfunction and apoptosis in various tissues.     

T-cell activation Rho GTPase–activating protein expression varies with inflammation location and severity in Crohn's disease

Background

The T-cell activation Rho GTPase–activating protein (TAGAP) gene has a regulatory role in T cell activation. We have previously suggested a correlation between the TAGAP-associated single nucleotide polymorphism rs212388 and protection from anal sepsis in Crohn's disease (CD) patients. The present study sought to evaluate TAGAP's expression in colonic tissue of CD patients with varying disease severity and location.

Materials and methods

Five transverse, 17 left, and five sigmoid colectomy specimens from 27 CD patients with varying disease severity (16 male, mean age at diagnosis 26.4 ± 2.2 y) were evaluated for TAGAP messenger RNA expression. Fisher exact, Mann–Whitney, and Welch two-sample t-tests were used for statistical evaluation. Immunohistochemistry confirmed results.

Results

Patients with tissue demonstrating lower TAGAP messenger RNA expression (less than the overall mean) were younger at diagnosis (mean age 21.1 ± 6.3 versus 32.5 ± 13 y, P = 0.009). Increased TAGAP expression was seen in moderate or severely diseased tissue versus tissue with no or mild disease (RQ = 1.3 ± 0.34 versus 0.53 ± 0.09, P = 0.050). This was the most dramatic in the sigmoid colon (P = 0.041). TAGAP expression was increased in more distal tissue with a significant difference seen when comparing transverse versus sigmoid colon with moderate or severe disease (0.51 ± 0.14 versus 1.9 ± 0.37, P = 0.049).

Conclusions

Colonic expression of TAGAP in CD patients varied according to disease severity and location, being the most elevated in patients with severe disease in the sigmoid colon. Whether changes in TAGAP expression are a result of disease response or inherent to the disease pathophysiology itself remains to be determined. This gene warrants further investigation for its role in CD.     

Radiation exposure from head computed tomography scans in pediatric trauma

Background

We have previously reported that children receive significantly less radiation exposure after abdominal and/or pelvis computed tomography (CT) scanning for acute appendicitis when performed at our children's hospital (CH) rather than at outside hospitals (OH). In this study, we compare the amount of radiation children receive from head CTs for trauma done at OH versus those at our CH.

Methods

A retrospective chart review was performed on all children transferred to our hospital after receiving a head CT for trauma at an OH between July 2012 and December 2012. These children were then blindly case matched based on date, age, and gender to children at our CH.

Results

There were 50 children who underwent head CT scans for trauma at 28 OH. There were 21 females and 29 males in each group. Average age was 7.01 ± 0.5 y at the OH and 7.14 ± 6.07 at our CH (P = 0.92). Average weight was 30.81 ± 4.69 kg at the OH and 32.69 ± 27.21 kg at our CH (P = 0.81). Radiation measures included dose length product (671.21 ± 22.6 mGycm at OH versus 786.28 ± 246.3 mGycm at CH, P = 0.11) and CT dose index (53.4 ± 2.26 mGy at OH versus 49.2 ± 12.94 mGy at CH, P = 0.56).

Conclusions

There is no significant difference between radiation exposure secondary to head CTs for traumatic injuries performed at OH and those at a dedicated CH.     

Novel functional role of heat shock protein 90 in protein kinase C-mediated ischemic postconditioning

Background

Previous studies have shown that heat shock protein 90 (HSP90) plays a vital role in ischemic preconditioning. The present study was designed to explore whether HSP90 might be responsible for cardioprotection in ischemic postconditioning (PostC).

Materials and methods

Rat hearts underwent 30 min of regional ischemia and 2 h of reperfusion in situ, and PostC was effected with three cycles of 30-s reperfusion and 30-s coronary artery occlusion at the end of ischemia. Ninety rats were randomized into five groups: sham; ischemia–reperfusion (I/R); PostC; 1 mg/kg HSP90 inhibitor geldanamycin (GA) plus PostC (PostC + GA1); and 5 mg/kg GA plus PostC (PostC + GA5). The GA was administered 10 min before reperfusion.

Results

Compared with the I/R group, the PostC group exhibited lower infarct size (46.7 ± 3.0% versus 27.4 ± 4.0%, respectively), release of lactate dehydrogenase and creatine kinase-MB (2252.6 ± 350.8 versus 1713.7 ± 202.4 IU/L, 2804.3 ± 315.7 versus 1846.2 ± 238.0 IU/L, respectively), cardiomyocyte apoptosis (48.4 ± 5.6% versus 27.6 ± 3.8%, respectively), and mitochondrial damage. These beneficial effects were accompanied by an increase in mitochondrial Bcl-2 levels and a decrease in Bax levels. In addition, mitochondrial protein kinase Cepsilon (PKCepsilon) was relatively low in the I/R group but significantly higher in the PostC group, whereas cytosolic PKCepsilon was relatively high in the I/R group but significantly lower in the PostC group, suggesting the translocation of PKCepsilon from cytosol to mitochondria during PostC. However, blocking HSP90 function with GA inhibited the protection of PostC and PKCepsilon mitochondrial translocation.

Conclusions

HSP90 is critical in PostC-induced cardioprotection, and its activity might be linked to mitochondrial targeting of PKCepsilon, the activation of which results in upregulation of its target gene, Bcl-2, and the inhibition of proapoptotic Bax in mitochondria.     

Flutamide fails to reduce resuscitation requirements in a porcine ischemia-reperfusion model

Background

Hemorrhagic shock and subsequent resuscitation can lead to ischemia-reperfusion injury, followed by multiorgan failure and death. Flutamide, a vasoactive nonsteroidal antiandrogen compound, is thought to improve tissue and organ perfusion. We tested whether administration of flutamide-cyclodextrin (FLU-CYD) alters physiologic parameters or resuscitation requirements in a porcine model of severe acidosis and shock secondary to combined hemorrhage + ischemia-reperfusion injury.

Methods and materials

Fifteen male pigs underwent a 35% blood-volume hemorrhage. Ischemia was induced by cross-clamping the supraceliac aorta for 50 min followed by reperfusion and resuscitation. FLU-CYD complex was administered during aortic clamping. Fluid resuscitation and epinephrine were titrated by protocol to maintain mean arterial pressure ≥40 mm Hg for 6 h. Sequential laboratory results were obtained and serum levels of FLU and 2-hydroxy-flutamide (FLUOH) were measured by mass spectrometry.

Results

Mean requirements for injured control swine were 14.6 (± 1.21 standard error of the mean [SEM]) L crystalloid saline and 0.59 (± 0.29 SEM) g epinephrine, compared with 16.30 (± 1.33 SEM) L and 0.54 (± 0.16 SEM) g, respectively, in the FLU-CYD group (both P > 0.05). There were no significant differences in central hemodynamics between control and experimental groups. No significant differences for pH, bicarbonate, fibrinogen, or international normalized ratio were evident. FLU-CYD resuscitation was associated with a significant increase in lactate levels compared with controls (10.1 versus 5.7 mmol/L, P < 0.05). Histologic injury was significantly increased in the livers of FLU-CYD compared with sham (P = 0.022). High serum levels of FLU and the active metabolite FLUOH were measurable throughout the resuscitation period.

Conclusions

Flutamide failed to show any benefit to resuscitation in a model of severe injury and was associated with increased acidosis, hemodilution, and liver injury compared with standard crystalloid resuscitation.     

Do laparoscopic skills transfer to robotic surgery?

Background

Identifying the set of skills that can transfer from laparoscopic to robotic surgery is an important consideration in designing optimal training curricula. We tested the degree to which laparoscopic skills transfer to a robotic platform.

Methods

Fourteen medical students and 14 surgery residents with no previous robotic but varying degrees of laparoscopic experience were studied. Three fundamentals of laparoscopic surgery tasks were used on the laparoscopic box trainer and then the da Vinci robot: peg transfer (PT), circle cutting (CC), and intracorporeal suturing (IS). A questionnaire was administered for assessing subjects' comfort level with each task.

Results

Standard fundamentals of laparoscopic surgery scoring metric were used and higher scores indicate a superior performance. For the group, PT and CC scores were similar between robotic and laparoscopic modalities (90 versus 90 and 52 versus 47; P > 0.05). However, for the advanced IS task, robotic-IS scores were significantly higher than laparoscopic-IS (80 versus 53; P < 0.001). Subgroup analysis of senior residents revealed a lower robotic-PT score when compared with laparoscopic-PT (92 versus 105; P < 0.05). Scores for CC and IS were similar in this subgroup (64 ± 9 versus 69 ± 15 and 95 ± 3 versus 92 ± 10; P > 0.05). The robot was favored over laparoscopy for all drills (PT, 66.7%; CC, 88.9%; IS, 94.4%).

Conclusions

For simple tasks, participants with preexisting skills perform worse with the robot. However, with increasing task difficulty, robotic performance is equal or better than laparoscopy. Laparoscopic skills appear to readily transfer to a robotic platform, and difficult tasks such as IS are actually enhanced, even in subjects naive to the technology.     

Treatment with a histone deacetylase inhibitor,valproic acid,is associated with increased platelet activation in a large animal model of traumatic brain injury and hemorrhagic shock

Background

We have previously shown that resuscitation with fresh frozen plasma (FFP) in a large animal model of traumatic brain injury (TBI) and hemorrhagic shock (HS) decreases the size of the brain lesion, and that addition of a histone deacetylase inhibitor, valproic acid (VPA), provides synergistic benefits. In this study, we hypothesized that VPA administration would be associated with a conservation of platelet function as measured by increased platelet activation after resuscitation.

Materials and methods

Ten swine (42-50 kg) were subjected to TBI and HS (40% blood loss). Animals were left in shock for 2 h before resuscitation with either FFP or FFP + VPA (300 mg/kg). Serum levels of platelet activation markers transforming growth factor beta, CD40 L, P-selectin, and platelet endothelial cell adhesion molecule (PECAM) 1 were measured at baseline, postresuscitation, and after a 6-h observation period. Platelet activation markers were also measured in the brain whole cell lysates and immunohistochemistry.

Results

Circulating P-selectin levels were significantly higher in the FFP + VPA group compared with the FFP alone group (70.85 ± 4.70 versus 48.44 ± 7.28 ng/mL; P < 0.01). Likewise, immunohistochemistry data showed elevated P-selectin in the VPA treatment group (22.30 ± 10.39% versus 8.125 ± 3.94%, P < 0.01). Serum sCD40L levels were also higher in the FFP + VPA group (3.21 ± 0.124 versus 2.38 ± 0.124 ng/mL; P < 0.01), as was brain sCD40L levels (1.41 ± 0.15 versus 1.22 ± 0.12 ng/mL; P = 0.05). Circulating transforming growth factor beta levels were elevated in the FFP + VPA group, but this did not reach statistical significance (11.20 ± 1.46 versus 8.09 ± 1.41 ng/mL; P = 0.17). Brain platelet endothelial cell adhesion molecule 1 levels were significantly lower in the FFP + VPA group compared with the FFP group (5.22 ± 2.00 pg/mL versus 7.99 ± 1.13 pg/mL; P = 0.03).

Conclusions

In this clinically relevant large animal model of combined TBI + HS, the addition of VPA to FFP resuscitation results in an early upregulation of platelet activation in the circulation and the brain. The previously observed neuroprotective effects of VPA may be due to a conservation of platelet function as measured by a higher platelet activation response after resuscitation.     

Large-for-size liver transplantation: a flowmetry study in pigs

Background

Ischemia–reperfusion injury is partly responsible for morbidity in pediatric liver transplantation. Large-for-size (LFS) liver transplantation has not been fully studied in the pediatric population, and the effects of reperfusion injury may be underestimated.

Materials and methods

Thirteen Landrace–Large white pigs weighing 23 kg (range, 17–38 kg) underwent orthotopic liver transplantation. They were divided into two groups according to the size of the donor body: LFS and control (CTRL). After transplantation, the abdominal cavity of the recipient was kept open and portal venous flow (PVF) was measured after 1 h. The ratio of recipient PVF (PVFr) to donor PVF was used to establish correlations with ischemia and reperfusion parameters. Liver biopsies were taken 1 h after transplantation to assess ischemia and reperfusion and to quantify the gene expression of endothelial nitric oxide synthase, interleukin 6, BAX, and BCL.

Results

Recipient weight, total ischemia time, and warm ischemia time were similar between groups. Among hemodynamic and metabolic analyses, pH, central arteriovenous PCO₂ difference, and AST were statistically worse in the LFS group than in the CTRL group. The same was found with endothelial nitric oxide synthase (0.41 ± 0.18 versus 1.56 ± 0.78; P = 0.02) and interleukin 6 (4.66 ± 4.61 versus 16.21 ± 8.25; P = 0.02). In the LFS group, a significant decay in the PVFr was observed in comparison with the CTRL group (0.93 ± 0.08 and 0.52 ± 0.11, respectively; P < 0.001).

Conclusions

The implantation of a graft was responsible for poor hemodynamic status of the recipient 1 h after transplantation. Furthermore, the LFS group demonstrated markers of ischemia and reperfusion that were worse when compared with the CTRL group and exhibited a more significant decrease in PVF from donor to recipient.     

Delayed remote preconditioning induces cardioprotection: role of heme oxygenase-1

Background

The role of heme oxygenase-1 (HO-1) in the cardioprotection induced by delayed remote ischemic preconditioning (DRIPC) has not been investigated. Therefore, this study was designed to investigate whether HO-1 is involved in DRIPC-mediated cardioprotection in an isolated perfused rat heart model.

Materials and methods

Isolated rat hearts were subjected to 30 min ischemia followed by 60 min reperfusion. DRIPC (four cycles 5-min occlusion and 5-min reflow at the unilateral hind limb once per day for 1, 2, or 3 d before heart isolation, abbreviated as D1RIPC, D2RIPC, or D3RIPC respectively). Infarct size, myocardial troponin levels, and heart function were measured. The protein and messenger RNA levels of HO-1 were determined.

Results

DRIPC facilitated postischemic cardiac functional recovery and decreased cardiac enzyme release. The infarct size-limiting effect of DRIPC was more pronounced in the D3RIPC group (10.22 ± 2.57%) than the D1RIPC group (22.34 ± 4.02%, P < 0.001) or the D2RIPC group (14.60 ± 3.13%, P = 0.034). These effects in the D1RIPC group could be blocked by Zinc Protoporphyrin IX (ZnPP) (an HO-1 specific inhibitor). DRIPC-mediated cardioprotection was associated with enhanced HO-1 protein expression (D1RIPC, 0.11 ± 0.03; versus 0.15 ± 0.06 in the D2RIPC group, P = 0.06; versus 0.20 ± 0.04 in the D3RIPC group, P = 0.04) and messenger RNA levels of HO-1 expression.

Conclusions

Our findings suggest that HO-1 is involved in the cardioprotection induced by DRIPC, and that increase in the number of preconditioning stimuli may enhance cardioprotective effects accompanied with increased HO-1 level.     

Dietary phytoestrogens inhibit experimental aneurysm formation in male mice

Background

The purpose of these experiments was to test the hypothesis that dietary phytoestrogens would diminish experimental aortic aneurysm formation.

Materials and methods

Six-wk-old C57BL/6 mice were divided into groups, fed either a diet with minimal phytoestrogen content or a regular commercial rodent diet with high phytoestrogen content for 2 wk. At the age of 8 wk, aortic aneurysms were induced by infusing the isolated infrarenal abdominal aorta with 0.4% elastase for 5 min. Mice were recovered and the diameter of the infused aorta was measured at postoperative days 3, 7, and 14. Abdominal aorta samples were collected for histology, cytokine array, and gelatin zymography after aortic diameter measurement. Blood samples were also collected to determine serum phytoestrogens and estradiol levels. Multiple-group comparisons were done using an analysis of variance with post hoc Tukey tests.

Results

Compared with mice on a minimal phytoestrogen diet, mice on a regular rodent diet had higher levels of serum phytoestrogens (male, 1138 ± 846 ng/dL; female, 310 ± 295 ng/dL). These serum phytoestrogen levels were also much higher than their own endogenous estradiol levels (109-fold higher for males and 35.5-fold higher for females). Although aortic diameters of female mice were unaffected by the phytoestrogen concentration in the diets, male mice on the regular rodent diet (M+ group) developed smaller aortic aneurysms than male mice on the minimal phytoestrogen diet (M− group) on postoperative day 14 (M+ 54.8 ± 8.8% versus M− 109.3 ± 37.6%; P < 0.001). During aneurysm development (postoperative days 3 and 7), there were fewer neutrophils, macrophages, and lymphocytes in the aorta from the M+ group than from the M− group. Concentrations of multiple proinflammatory cytokines (matrix metalloproteinases [MMPs]; interleukin 1β [IL-1β]; IL-6; IL-17; IL-23; monocyte chemoattractant protein-1; regulated on activation, normal T cell expressed and secreted; interferon γ; and tumor necrosis factor α) from aortas of the M+ group were also lower than those from the aortas of the M− group. Zymography also demonstrated that the M+ group had lower levels of aortic MMP-9s than the M− group on postoperative day 14 (P < 0.001 for pro-MMP-9, P < 0.001 for active MMP-9).

Conclusions

These results suggest that dietary phytoestrogens inhibit experimental aortic aneurysm formation in male mice via a reduction of the inflammatory response in the aorta wall. The protective effect of dietary phytoestrogens on aneurysm formation warrants further investigation.